PDF attachments forwarded from iPhone arrive as text

Question

I receive an email on my iPhone with a PDF attachment I can view the PDF and it is fine. If I forward that email internally (within our mail domain) it is fine. However, when I forward the email to an external address the PDF arrives as text instead of as an attachment. Sample below:
--Apple-Mail-4--1051191225
Content-Transfer-Encoding: base64
Content-Type: text/html;
charset=f-8
PGh0bWwPGJvZHkgYmdjb2xvcj0iI0ZGRkZGRiIPGRpdj5Gb3IgeW91PGJyPjxicj4tIE5laWw8
L2Rpdj48ZGl2Pjxicj5CZWdpbiBmb3J3YXJkZWQgbWVzc2FnZTo8YnI+PGJyPjwvZGl2PjxibG9j
a3F1b3RlIHR5cGU9ImNpdGUiPjxkaXYPGI+RnJvbTo8L2IICJNYXR0aGV3IENvb2siICZsdDs8 etc etc
Any advice as to why this might be happening and how to fix it?

Answer 1

I'm not sure if this is the same issue, but it sounds very similar.
I've notice when I attach PDFs I've either created from a scan or from Print -> PDF -> Save to PDF, if the file size is within a certain limit, it shows a preview (linked to the program Preview, maybe?) image of that PDF in the Mail Message window, rather than the icon. I can right-click on the image and choose "View as icon" which... does the obvious. But if I try to print that Mail message, it prints the PDF preview instead of the icon.
Recipients using Mac's Mail program also see the preview image rather than the icon when they open the message.
I've gone through the Preference options and every other menu up there, and I can't for the life of me find a way to turn off this preview image. Any ideas? Am I missing something?
The same small PDFs also display in Finder with an icon that is a miniaturized image of the preview image. Can I turn off the option to save a preview of these documents/files?
Thank you in advance.
-E
eMac PowerPC G4   Mac OS X (10.4.6)